Abstract: The squeeze casting process of aluminum alloy gearbox case was analyzed by numerical simulation. The shrinkage porosity defects distribution of the box in the original process plan was predicted.A reasonable cooling system was added by analyzing the causes. On this basis, the multi-objective optimization of the process parameters was performed by using orthogonal tests. The results show that the optimized box has no shrinkage defects, and the secondary dendrite spacing decreases to 36.37 μm.The correctness of the squeeze casting process was verified by metallographic analysis.